<第一行代码>笔记一

一、隐藏Activity标题：

requestWindowFeature(Window.FEATURE_NO_TITILE);//要在setContentView()之前调用

二、向下一个活动传递数据（在要启动的Activity中提供一个方法给上一个Activity调用）

启动Activity的最佳写法：

public class SecondActivity extends BaseActivity  {

public static void actionStart(Context context, String data1, String data2)  {

Intent intent = new Intent(context, SecondActivity.class); 

intent.putExtra(data1);

intent.putExtra(data2);

context.startActivity(intent);

}

}

三、返回数据给上一个Activity

（1）、调用startActivityForResult(intent,requestcode);

（2）、在第二个Activity中，

Intent intent = new Intent();

intent.putExtra("data","ss");

setResut(resultcode,intent);

（3）、重写onActivityResult方法

四、Activity被回收了怎么办？

重写Activity的onSaveInstanceState（Bundle outState）方法，

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    if (savedInstanceState != null) {
        //取出保存的数据
        
    }
}

@Override
public void onSaveInstanceState(Bundle outState, PersistableBundle outPersistentState) {
    super.onSaveInstanceState(outState, outPersistentState);
    outState.putString("data","data");
}

五、随时随地退出程序

/**
 * 基础Activity，所有Activity继承这个Activity
 * Created by Administrator on 2016/7/14.
 */
public class BaseActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d("BaseActivity", getClass().getSimpleName());//知晓当前是在哪一个活动
        ActivityCollector.addActivity(this);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        ActivityCollector.removeActivity(this);
    }
}

/**
 * Activity管理
 * Created by Administrator on 2016/7/14.
 */
public class ActivityCollector {

    public static List<Activity> activities = new ArrayList<>();

    public static void addActivity(Activity activity) {
        activities.add(activity);
    }

    public static void removeActivity(Activity activity) {
        activities.remove(activity);
    }

    /**
     * 退出程序时调用这个方法
     */
    public static void finishAll() {
        for (Activity activity : activities) {
            if (!activity.isFinishing()) {
                activity.finish();
            }
        }
    }
}

          

六、设置全屏

//全屏
		getWindow().setFlags(WindowManager.LayoutParams. FLAG_FULLSCREEN ,
				WindowManager.LayoutParams. FLAG_FULLSCREEN);